For high-power and radiofrequency applications, semiconductor products are often fabricated using drain-extended metal-oxide-semiconductor (DEMOS) transistor devices. DEMOS devices advantageously combine short-channel operation with high current handling capabilities, relatively low drain-to-source on-state resistance, and the ability to withstand high blocking voltages without suffering voltage breakdown failure (high breakdown voltage ratings).
DEMOS devices utilize a drift region between the channel under the gate and a region, such as the drain. The drift region ensures a significant portion of the drain-source voltage drops and, hence, prevents the channel from overheating and causing damage to the device.
Conventional fabrication processes typically require deposition of a blocking layer over drift regions in order to prevent the drift regions from receiving source/drain ion implantation. Further, the blocking layer inhibits silicidation of the drift regions during later silicidation processes. However, when used with replacement gate processes, the blocking layer hinders the removal of the temporary or dummy gate structures. Further, the deposition and patterning of the blocking layer itself can unnecessarily increase manufacturing costs and lengthen the manufacturing process.
Accordingly, it is desirable to provide methods for fabricating integrated circuits utilizing replacement gate structures and drift regions without blocking layers. In addition, it is desirable to provide methods for fabricating integrated circuits which use photoresist to protect drift regions from ion implantation. Furthermore, other desirable features and characteristics will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and the foregoing technical field and background.